<!DOCTYPE html>
<html>
<head lang="en">
    <meta charset="UTF-8">
    <title></title>
</head>
<body>
<script>
    var num = 10;
    console.log(typeof !!num);
   /* a++;
    a=a+1*/;
    var num = "0";
    /*num++;
    console.log(num);*/
    num = num +1;
    console.log(num);


</script>
</body>
</html>